The giant Three Gorges Dam on the Yangtze risks choking China’s largest river port with silt and sewage and will displace 500,000 people unnecessarily, engineers and academics have warned the country’s political leaders. A group of 53 experts, including former Three Gorges engineers, dam experts, parliamentarians and cultural officials, have signed a petition released by Three Gorges Probe, a Toronto-based campaign group. This offers the most detailed evidence that officials are planning to fill the dam’s 350-mile reservoir to its maximum depth up to a decade early, apparently to maximise revenue from electricity generation. The dam is due to be ready in 2009, despite warnings from Chinese and international engineers that it will be an economic, environmental and archeological disaster. At least 1.13 million people must be moved, although a mere 220,000 had been resettled by the end of last year. The original plan called for the water level to be raised slowly, to monitor the build-up of silt, which threatens Chongqing port, of 30 million people, just upstream of the dam. The experts dismiss the official solution, building three dams to catch the silt, and call for the Three Gorges to be kept to a lower water level for at least 10 years. This would cut the number of farmers to be moved by 500,000 and allow Chongqing to build sewage plants.